Basic Kolsch - High pH Question?

[CadillacAndy]

So I did my first run with my new cooler MLT and decided to go with something with minimal grains in order to really get a good handle on my system. I tested my water first, and the pH was 7.6. I proceeded to go thru the process, cooled my wort down to 70F and took another pH reading - it was 6.6.

I've made several partial mash/partial extract batches - usually stouts and porters - and the pH for those has been in the 5.2 - 5.7 range.

My grain bill for my AG Kolsch was:
8.5lbs German 2-row Pils
8oz Vienna malt

Based on my expected gravity reading (1.049) and actual measured gravity (1.052) it looks like my efficiency was around 80%.

So my question is what could have caused the pH to get so high? I have a copper manifold in my cooler and a copper immersion chiller. I soaked and cleaned all of that before I used it. I also used a new aluminum kettle - I preboiled 7 gallons of H20 to get the inside oxidized before I used it, and then cleaned that with oxyclean and triple rinsed. Could any of those metals leech into my wort to cause the high pH number? I'm not a scientist by any means, so forgive my ignorance if that's not how things work. Do hops have a major effect on pH? I used 1.75oz of Williamette (I forgot to get Hallertau from the LHBS - doh!)

While I'm not overly concerned - I've learned to relax and fun with everything, I'd like to end up with the best possible end product.

 

[Buna_Bere]

I've been reading about understanding pH on Kai's site, here's a link

Link to Kai's site on mash pH

I'll take a guess as to your high pH question, the beers you made before were darker beers. Darker malts are usually more acidic, pushing the pH lower. Since your last batch is all lighter grains, which are less acidic than the darker malts, the grains weren't able to lower the pH to the levels you've measured before. You still got a great efficiency though. I highly recommend Kai's site.

 

[Nateo]

The pH of the water is basically meaningless. I have a pH of around 7.5 but my carbonates are over 400ppm. It's the buffering capacity (alkalinity) of the water that's the problem. Do you have a detailed water report? That's where I'd start.

 

[CadillacAndy]

Thanks for the replies guys! I appreciate it. Looks like a water test may be in order. I tried checking the water company's reports, but they don't give an analysis like what I'd need. Thanks again!

 

[BigEd]

Do not obsess about pH, it's only the facade. As has been already posted, forget about the pH of your water. It's the pH of the mash that's important and that result is strongly although not entirely related to the residual alkalinity and calcium content of the brewing water. Read the information about water in the Brewing Science section here as well as in a good basic homebrewing book like "How to Brew". Then get a water report for your supply that lists the content of the important brewing ions. If you can't get a suitable report from the water department send a sample to Ward Labs. Once you've done that you can probably make a simple calcium salt addition to take care of things.

 

[CadillacAndy]

Thanks Ed! I appreciate it. Now if only patience was something I could learn from this forum or a book, I'd be all set.